Fingerprint is a line pattern, which is formed by protrusions (i.e., peaks) and grooves (i.e., valleys) in a line-shaped arrangement, of the epidermal layer of a finger. Because fingerprints have the characteristics of life long invariability, uniqueness and convenience, fingerprint has become a synonym of biometric identification and has applied in identity authentication and identification field such as security facilities, time attendance systems, and the like.
Fingerprint identification mainly adopts the capacitance-type sensing technology, a module for identification includes two layers opposed to each other, each layer comprises a plurality of electrode wires spaced apart from each other, the electrode wires of the upper layer and the lower layer are intersected with each other, and an induction capacitor is formed at each intersection; each induction capacitor is equivalent to a detection pixel, in the case of fingerprint detection, the induction capacitance between the electrode wires of the upper layer and the lower layer is changed due to the introduction of the electric field of a human body, because the peaks of the skin of the finger are relatively protruded out, and the valleys of the skin of the finger are relatively caved inward, the influence of the peaks and valleys to the induction capacitance are also different, the fingerprint information of the person who touches the module can be obtained through converting the variation of the induction capacitance into two dimensional image data, such that fingerprint comparison work can be conducted.
After the fingerprint identification module being integrated into the liquid crystal display device, so as to make the liquid crystal display device has full screen fingerprint identification function, the fingerprint identification module has a lot of structural layers, and the liquid crystal display device also has a lot of structural layers to realize display function, therefore, the liquid crystal display device with full screen fingerprint identification function has a lot of structure components, and a thickness of the liquid crystal display device is big.